Engine fan case grinder

Abstract

A device for grinding a fan case for a gas turbine engine to provide an eccentric opening. The device employs a rotatable hub mounted on the fan shaft by a pair of eccentric sleeves one surrounding the other for adjusting the eccentricity of the hub relative to the shaft.

I claim: 
     
       1. A grinder for the fan shroud of a gas turbine engine said engine including a shaft, the grinder mechanism including: a support structure attached to the engine shaft and including a pair of eccentric sleeves one surrounding the other;   a hub mounted on said structure;   a bar on said hub; and   a grinder on the outer end of the bar, said eccentric sleeves being turnable one with respect to the other for adjusting the eccentricity of the hub relative to the shaft.   
     
     
       2. A grinder as in claim 1 in which the eccentricity of the sleeves is the same so that in one position of the sleeves the eccentricities cancel out and rotation of the hub may be on the axis of the support shaft. 
     
     
       3. A grinder as in claim 1 including a hinged plate at the outer end of the bar with the grinder on said plate and an arm in said plate for moving the grinder radially against the surrounding shroud. 
     
     
       4. A grinder as in claim 1 including means for clamping the eccentric sleeves against rotation in any selected position of the sleeves. 
     
     
       5. A grinder as in claim 4 in which one sleeve is movable and the other fixed and the clamping means are positioned to mark the maximum eccentricity for the movable sleeve. 
     
     
       6. A grinder as in claim 1 in which the hub carries a second bar thereon in opposition to said first bar, said second bar carrying a weight to counterbalance the grinder. 
     
     
       7. A grinder for producing an eccentric surface on the fan shroud of a gas turbine engine, said engine having a shaft, the grinder mechanism including: a support structure for attachment to the end of the shaft and having means for holding the structure against rotation on the shaft, such structure including;   a pair of eccentric sleeves one surrounding the other, the outer sleeve being turnable with respect to the inner sleeve;   a hub journaled on said outer sleeve;   a bar on said hub extending radially therefrom;   a hinged plate on the outer end of said bar; and   a grinder on said plate and in a position to engage the shroud.   
     
     
       8. A grinder as in claim 7 in which the axis of the hinged plate is parallel to the shroud to be ground. 
     
     
       9. A grinder as in claim 7 in which the plate has an arm by which the plate may be moved to urge the grinder against the shroud. 
     
     
       10. A grinder as in claim 9 in which the arm has adjustable limit stops to limit the arm movement whereby to limit the grinder movement. 
     
     
       11. A grinder as in claim 7 in which the hub has a second bar in opposition to the first bar and said second bar carries a balance weight for the grinder. 
     
     
       12. A grinder as in claim 7 in which the outer sleeve carries thereon means for clamping the sleeves in fixed relation one to the other and said clamping means are positioned to mark the maximum eccentricity of the movable sleeve.